• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.844-847
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• 1997

In this paper, scheduling problem is dealt for the minimization of due date penalty for the customer order. Multiproduct batch processes have been dealt with for their suitability for high value added low volume products. Their scheduling problems take minimization of process operation for objective function, which is not enough to meet the customer satisfaction and the process efficiency simultaneously because of increasing requirement of fast adaptation for rapid changing market condition. So new target function has been suggested by other researches to meet two goals. Penalty function minimization is one of them. To present more precisely production scheduling, we develop new scheduling model with penalty function of earliness and tardiness We can find many real cases that penalty parameters are divergent by the difference between the completion time of operation and due date. That is to say, the penalty parameter values for the product change by the customer demand condition. If the order charges different value for due date, we can solve it with the due date period. The period means the time scope where penalty parameter value is 0. If we make use of the due date period, the optimal sequence of our model is not always same with that of fixed due date point. And if every product have due date period, due date of them are overlapped which needs optimization for the maximum profit and minimum penalty. Due date period extension can be enlarged to makespan minimization if every product has the same abundant due date period and same penalty parameter. We solve this new scheduling model by simulated annealing method. We also develop the program, which can calculate the optimal sequence and display the Gantt chart showing the unit progress and time allocation only with processing data.

• 산업경영시스템학회지
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• 제31권4호
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• pp.21-28
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• 2008

본 연구는 반도체 제조공정에서 사용되는 단일 Burn-In oven에서의 Total weighted earliness와 Tardiness를 최소화하기 위한 생산 스케줄링을 결정하는 문제를 다룬다. 본 연구에서는 모든 작업은 상시에 시작가능하고 각각은 서로 다른 가중치를 가지고 있다고 가정하였다. 일반적으로 단일 Burn-In oven은 다양한 작업들이 동시에 가능한 Batch processing 기계이다. 따라서 다양한 작업들로 구성된 하나의 Batch의 Processing time은 그 Batch 내에 있는 가장 긴 Processing time을 가지는 작업에 의해 결정된다. 본 연구에서 Batch size는 미리 결정되지 않은 상황이라고 가정한 후, 최적의 Batch 개수와 작업의 순서를 결정하기 위해 유전자 알고리즘을 적용하였다. 수리적 예제를 통해서 다양한 접근방법의 성능들을 비교한 결과, 유전자 알고리즘이 Total weighted earliness와 Tardiness를 최소화하는데 가장 뛰어난 성능을 가지고 있음을 알 수 있다.

• 경영과학
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• 제17권2호
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• pp.67-73
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• 2000

This paper describes a scheduling support system for a plant where the machine environment may be modeled as non-identical parallel machine lines (NPML). That is, there are a number of stages in series with various different-capability-machines at each stage. Arriving continuously are jobs with their specific due dates, processing times and candidate processing machines. We’ve developed a real-time scheduling module in conjunction with a supporting production information system which supplies necessary data to the module. This scheduling module is one of the 9 modules in this system, and is composed of both a scheduling interface and a production monitoring interface. This module allows users to generate many candidate schedules by selecting their business policies. The selective arguments which are available consist of allocation costs, batch sizes and machine selection intervals. They are now being implemented at a powder metallurgy plant.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.825-827
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• 1989

A heuristic model which determines the scheduling of serial flowshops with minimization of the makespan is proposed for an idealized batch chemical plant. It generates an initial sequence by heuristic reasoning and improves it recursively until no improvement is possible. The heuristic reasoning is based on Johnson's Rule which gives the sequence with the minimum makespan for a two-unit flowshop. The evolutionary step searches the neighborhood of the current sequence for sequences with lower makespan. The robustness of this model is also examined by comparing the minimum makespan of literature examples with the theoretical one.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1998년도 제13차 학술회의논문집
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• pp.455-460
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• 1998

We propose robust MILP model for scheduling and design of multiproduct batch processes in this paper. Recent stochastic modeling approaches considering uncertainty have mainly focused on maximization of expected NPV. Robust model concept is applied to generate solution spectrum in which we can select the best solution based on tradeoff between robustness measure and expected NPV. Robustness measure is represented as penalty term in the objective function, which is Upper Partial Mean of NPV. We can quantify solution robustness by this penalty term and maintain model as MILP form to be computationally efficient. An example illustrates the effectiveness of the proposed model. In many cases sufficient robustness can be guaranteed through a little reduction of expected NPV.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 1999년도 추계학술대회 및 정기총회 : 정보통신기술의 활용과 21세기 전자상거래
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• pp.13-13
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• 1999

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.56.6-56
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• 2002

1. Introduction 2. Process description 2.1 Process description 2.2 Assumption 3. Mathematical model 3.1 MILP model for cintinuous part 3.2 LP model for batch part 4. Exapmles and Results 5. Conclusion. Acknowledgement. Reference.

• 제어로봇시스템학회논문지
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• 제9권9호
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• pp.727-735
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• 2003

The determination of completion time constitutes an important step in developing algorithms for short-term production scheduling. Existing completion time algorithms of multi-product batch processes often assume that intermediate storage tanks are always available when it is needed. In this paper, we consider a serial multi-product batch plants with ZW and NIS policy intermediate storge tank. We limit storage residence time and allocated products in the intermediate storage tank to minimize the quality change of the stored material as well as to reduce the clearing time during product change. A set of recurrence relations is suggested to calculate the completion times for the given batch sequence of products on all processing units. Also analytic solution for the suggested model is solved by a graphical method. The effectiveness of these results is proved by a few illustrative examples.

• 제어로봇시스템학회논문지
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• 제5권6호
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• pp.714-723
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• 1999

This paper presents a short-term scheduling algorithm for the operation of steelmaking processes. The scope of the problem covers refining of the hot iron transferred form a blast furnace, ladle treatment, continuous casting, hot-rolling, and coiling for the final products that should satisfy the given demand. The processing time at each unit depends on how much the batch amount is treated, and te dedicated intermediate storage with finite capacity between the units is considered. Resource constraints and initial amount of each state are incorporated into the presented scheduling model for the algorithm of on-line scheduling. We propose amixed integer linear programming (MILP) model with two objectives for the scheduling. The first is to maximize the total profit while atisfying the due date constraint for each product. And the second is to minimize the total processing time, makespan, while satisfying the demand for each product. Especially, we observe the effect of penalizing the intermediate storage and the inventory level of the final product on the scheduling results.

• Korean Chemical Engineering Research
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• 제46권2호
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• pp.316-329
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• 2008

최근의 급변하는 시장 상황의 변화와 제품의 수요에 대한 다양한 요구는 회분식 공정에 의한 다품종 소량생산으로의 전환을 가져오게 하였다. 이러한 회분식 공정은 주로 정밀 화학 관련 제품들인 의약품, 생화학 제품, 농약, 고분자 소재 등의 생산에 사용되어 왔지만, 근래에는 윤활유, 섬유, 석유 화학, 식품 같은 제품의 생산에도 널리 적용되고 있다. 그러나 회분식 공정은 원료의 공급, 제품의 가격 등과 같은 불확실 변수에 의한 조업의 변화가 자주 발생하는 단점이 있다. 이러한 조업의 변화는 조업시간의 변동과 각 부분별 예측량이 달라져 시장 경쟁력을 잃게 된다. 이에 공급망 상에 위치한 각 부서별, 기업별 협력과 조정을 통한 총체적 관점에서의 최적화를 추구하는 공급사슬 관리에 관한 관심이 고도되고 있다. 이에 본 논문에서는 회분식 공정에 공급사슬 관리 기법을 도입하여 원자재의 구매에서부터 분배에 이르는 전과정에 대한 총체적인 최적해를 찾고 각 공급사슬간의 영향력을 조사, 분석하였다. 또한 본 논문에서는 생산계획과 상세일정계획 모델의 통합과 수요에 대한 단계별 예측을 통해 시장 변화와 불확실 변수(uncertainty)에 대한 적절한 대응방안을 모색하여, 회분식 공정에서의 공급사슬 관리 모델을 개발하였다. 이와 함께 각각의 공급사슬간 인터페이스를 통하여 정보와 물류의 통합이 이루어지게 하여, 실제 주문과 수요의 변화에 대하여 생산계획, 구매계획, 일정계획 및 분배계획을 수립하여 안정적인 공급이 이루어지게 하였다.